Zigzag sewing machines



Sept. 15, 1964 Filed Dec. 22, 1961 V. J. SIGODA ZIGZAG SEWING MACHINES 4Sheets-Sheet 1 74 2 1 lIllll p A III! as Em-um .g-flllll s m 8 INVENTOR.

Karo d. \SIGODH Sept. 15, 1964 v. J SIGODA ZIGZAG SEWING MACHINES 4Sheets-Sheet 2 Filed Dec. 22, 1961 IN VENTOR. More a}. 5/600 Se t. 15,1964 v. J. SIGODA ZIGZAG SEWING MACHINES 4 Sheets-Sheet 3 Filed Dec. 22,1961 INVENTOR. Karo? d. SIGQO4 Sept- 15, 1964 v. J. SIGODA 3,148,646

ZIGZAG smwznc MACHINES Filed Dec. 22, 1981 4 Sheets-Sheet 4 i E IN VENTOR.

l Illlll BY :7 nu 7.0 B6 4rrop/ve'y United States Patent York Filed Dec.22, 1961, Ser. No. 161,734 6 Claims. (Cl. 112-158) This inventionrelates to sewing machines capable of high speed production of zigzagstitching. It also relates to mechanisms which may be added to existingsewing machines of either the lockstitch or two thread chainstitch typesto convert such machines for the production of zigzag stitching of thosetypes.

One feature of the invention is the provision of mechanism which may bereadily attached to existing sewing machines such as typically alockstitch machine of the Singer 451K class to produce lateral movementof the needle concurrently with the usual vertical reciprocation.Another feature is the provision of mechanism which not only guides theneedle so that it enters the work perpendicularly regardless of thelateral movement of the needle but also compensates for the inherentdifference in timing of the loop-taker at opposite extremes of thelateral movement of the needle.

Such mechanisms may be applied to existing sewing machines to produceeither zigzag lockstitching or two thread chainstitching. New sewingmachines may be designed to take advantage initially of the disclosedfeatures, or alternately, stripped down versions of new lockstitchsewing machines may be expressly manufactured for such conversion byinclusion of these features to produce high speed zigzag sewingmachines. In the latter case, in those machines having reverse feedaction, new varieties of zigzag sewing machines having reverse feedaction may be made available.

Since there are numerous plain lockstitch sewing machines alreadyavailable, many of which are surplus for use as lockstitchers, it nowbecomes relatively inexpensive to produce the more desirable and moreversatile zigzag type of sewing machine. This is of significant economicadvantage as the owner may now recoup a dormant investment by suchconversions when such machines are no longer needed for the initialpurpose. It also makes possible a reduction in the capital investment inmachines and lessens the storage requirements for various types ofsewing machines when they may be readily converted from one stitch typeto another either temporarily or permanently.

In certain aspects, this application is a continuationin-part of pendingapplications Serial No. 30,682, filed May 20, 1960, and Serial No.151,680, filed November 13, 1961, now abandoned. In application SerialNo. 30,682, mechanisms are disclosed for converting lockstitch sewingmachines for the production of two thread chainstitching. Thesemechanisms provide an underlooper operating transversely to the line offeed and a novel underlooper thread presentor operating along the lineof feed which cooperates with the vertically reciprocating needle toform the two thread chainstitch. In application Serial No. 151,680,mechanism is disclosed for use with a reverse feed action lockstitchmachine so converted which assures poistive two thread chainstitchformation when the feed action is reversed.

When the new mechanisms disclosed herein are incorporated into alockstitch machine converted in accordance with application Serial No.30,682, all the advantages inherent in this new family of two threadchainstitch machines are made available in a zigzag sewing machine.These include the use of a much shorter and therefore stiffer needle, ashorter needle-bar stroke while maintaining adequate clearance betweenthe end of the needle ice and the surface of the work, and the use ofthe thread presentor about whose limbs the underlooper thread triangleis formed. The use of the presentor desensitizes the timing andpositioning of the underlooper in meeting the needle and makes the useof a compound motion underlooper no longer necessary. This new memberalso acts to control and hold the needle thread loop previouslyintercepted by the underlooper out of the path of theneedle as itintercepts the newly formed underlooper thread triangle. Since thiscombination of features makes possible positive two thread chainstitchformation at high operating speeds in the region of six thousandstitches per minute, the additional mechanisms disclosed herein makepossible production of a zigzag two thread chainstitch sewing machinecapable of operating at speeds exceeding five thousand stitchpenetrations per minute.

The mechanism which provides for the perpendicular entry of the needleinto the work contributes to this high speed performance capability asit is arranged to guide the needle ahnost down to the work. This guidedperpendicular entry minimizes needle deflection, and hence possibleneedle breakage, which may occur when the needle is required topenetrate todays hard surfaced and tough synthetic fabrics at an angleat high velocity. Perpendicular guidance despite the lateral shifting ofthe needle is made possible by separating the needle-bar into twoportions. One is drive portion corresponding to the conventionalneedle-bar and the other is a needle-carrier which is guidedperpendicularly regardless of its lateral position.

The desired aspect is maintained by the use of a pair of linksconnecting the two portions in conjunction with a vertical guideway. Thelinks are arranged however so that they alone are capable of holding theneedle-carrier in perpendicular attitude without the assistance of thewalls of the guideway. This not only minimizes wear in the Walls of theguideway but makes the desired needle entry possible even if wear insuch walls does occur.

Another feature is the arrangement of the parts which provide thelateral movement to the needle and guide it, in such manner that aminimum of mass is in motion and this contributes to smooth operation athigh speed.

The linkage mentioned is arranged so that it provides compensation forthe difference in timing of the loop-taker at each extreme of thelateral shifting of the needle. In any sewing machine the movements ofthe needle and the loop-taker (the threaded underlooper for a two threadchainstitch or the hook and bobbin for a lockstitch) are coordinated sothat the point of the loop-taker meets the needle in the scarf justabove the eye shortly after the needle reverses direction and isascending. This condition occurs in a zigzag machine only at the medianposition of the lateral throw of the needle. At either extreme thereof,the loop-taker travels either a shorter or longer distance to meet theneedle, and is therefore earlier or later in meeting the needle thanwhen the needle reciprocates on its median line.

When the range of vertical movement of the needle is held constant, thepoint of the loop-taker meets the needle in a different verticalposition of the needle for either extreme of the lateral movement. Whenthe needle is penetrating at the inner side of the zigzag seam it willnot have reached as high a point in its ascent as it will reach when theneedle is penetrating at the outer edge of the zigzag seam. In thislatter instance, since the loop-taker must take longer to reach themeeting point, the eye of the needle may have risen above the point atwhich the loop-taker can intercept the needle thread loop.

To compensate for this inherent timing difference, the linkageconnecting the two portions of the needle-bar has been arranged so thatit not only provides a flexible connection between the two, but so thatat one extreme of the lateral movement of the needle the stroke of theneedle-bar and needle-carrier combination is in etfect lengthened sothat it takes somewhat longer for the eye of the needle to reach thepoint in its ascent at which it is desirable that the loop-taker meetit. This is accomplished by pivoting the linkage at two spaced points,and this arrangement in conjunction with the two movements supplied tothe needle-carrier changes the overall length of the combination. It ispossible by suitable positioning of the pivots to arrange this change ofoverall length so that the combination may have a shorter stroke at oneextreme of the lateral throw than at the median position of needlereciprocation, and a somewhat longer stroke at the other extreme oflateral throw than at the median position. This may afford bettercompensation.

Other features will in part be obvious and in part will be pointed outin the following description, it being understood that the principles ofthe invention may be incorporated into other sewing machines whether ofthe particular brand of manufacture mentioned or others, so long as thedisclosed principles are compatible with their construction. It shouldtherefore be understood that the following description and the drawingsare merely illustrative and should not be construed in a limiting sense.

In the accompanying drawings:

FIG. 1 is a front elevational view of an industrial type sewing machinerepresentative of such widely used lockstitch sewing machines as theSinger 400, 451 and 600 classes, which has been converted for zigzagstitching of the two thread chainstitch type both in accordance withthis disclosure and that of application Serial No. 30,682; portions ofthe machine having been broken away and some shown partly in section toindicate the driving arrangements for the mechanisms which are added;

FIG. 2 is an end elevation of the head end of the converted sewingmachine shown in FIG. 1;

FIG. 3 is an enlarged fragmentary view of a portion of the machine shownin FIG. 1, partly in section, indicating the drive mechanisms for theunderlooper and the underlooper thread presentor and the mechanism whichshifts the thread presentor in synchronism with the lateral movements ofthe needle;

FIG. 4 is an enlarged fragmentary view of another portion of the machineshown in FIG. 1, showing the linkage connecting the needle-bar and theneedle-carrier and for guiding the needle for perpendicular penetrationof the work; indicating in broken line the position of the linkage andother members when the needle is at the other extreme of its lateralmovement; and showing in section the means for changing the centralposition of the needlecarrier;

FIG. 5 is a sectional view taken on line 5-5 of FIG. 4; and

FIG. 6 is a detail view taken on line 6-6 of FIG. 4.

The Sewing Machine The sewing machine consists of a cloth-plate 1 fromone end of which rises the standard 2 of a hollow bracketarm 3overhanging the cloth-plate and terminating at its free end in aneedle-head 4. Rotatably supported in the bracket-arm 3 is thehorizontally disposed main-shaft carrying at one end belt-pulley 6.Within the bracket-arm, the main-shaft carries a peripherally groovedpulley 8 connected by a clip-belt 9 disposed within the arm-standard toa similarly grooved pulley 10 carried by one end of the usual hook andfeed actuating shaft 11 which rotates oneto-one with the main-shaft andis disposed beneath the cloth-plate in substantial parallelismtherewith.

Before conversion for two thread chain-stitching, shaft 11 carries aninternal gear at its other end which is in mesh with a pinion 12 whichis attached to a horizontally disposed hook-shaft 14, the ratio of theinternal gear and pinion being such that the hook-shaft rotates twicefor each rotation of the main-shaft. The hook-shaft 14 carries at itsopposite end the hook which cooperates with the needle 15 in theformation of lockstitching.

The work is advanced past the stitch-forming members by feed mechanismof well known construction. Such feed mechanism produces the usual fourmotions of the feed-bar 16 and the feed-dog 18 carried thereby, thelatter, in conjunction with the presscr-foot 19 serving to ad Vance thework to the stitch-forming elements. A type of reverse feed mechanismwhich may be applied to such sewing machines is shown in US. Patent No.1,618,213 of February 22, 1927.

The stitch-forming mechanism for the lockstitch includes drive mechanismfor the needle-bar 20 and for the thread take-up mechanism. Theneedle-bar drive mechanism includes a crank-disk carried at the end ofmainshaft 5, and the crank-disk has extending therefrom a crank-pinwhich is connected by a link to reciprocate the needle-bar.

Other details of the basic lockstitch sewing machine may be obtained byreference to US. Patent No. 2,267,- 581 of December 23, 1941. That typeof lockstitch machine as so far described is not suitable formodification for zigzag stitching because the hook operates along theline of feed without any provision for shifting it laterally, and henceit cannot intercept the needle thread at the extremes of the lateralmovement given to the needle by the mechanism described herein. Themanner in which this type of lockstitch sewing machine may be modifiedfor zigzag stitching will be explained later.

However, other types of lockstitch sewing machines having hooksoperating transversely to the line of feed may be modified to producezigzag stitching, as may this type of lockstitch machine after it hasbeen converted for two thread chainstitching in accordance with thedisclosure of application Serial No. 30,682, since the latter conversionresults in a machine having a looptaker operating transversely to theline of feed. The instant invention will be further described inconjunction with such a conversion.

When the basic lockstitch machine described previously is to beconverted for two thread chainstitching, the hook is removed from shaft14 and the large internal gear is removed from shaft 11 and the latteris replaced by a small spur gear 21 which is the same size as pinion 12,and thus the former hook-shaft 14 now rotates in a oneto-onerelationship with mainshaft 5. Shaft 14 is then provided at its otherend (see FIG. 3) with eccentricblock 22 which carries stud 24 mounted ata selected distance from center to provide a predetermined amount ofrocking of the thread presentor arm 25 which is pivotally mounted onshaft 26. Arm 25 is connected by strap-link 28 with the stud on theeccentric-block 22 to produce a cycle of forward and rearward rocking ofthread presentor 29 carried by arm 25 for each rotation of main-shaft 5in time with the reciprocation of needle-bar 20.

The chainstitch underlooper is driven as follows. On the underside ofcloth-plate 1 (see FIG. 3) there is a downwardly projecting box 30 whichis normally sealed off by a gasketed cover plate which is replaced by agear support casting 31 when the converting mechanism is installed.Shaft 11 projects into this box and in the conversion is fitted withspiral gear 32 as well as with spur gear 21.

Gear 32 through a train of other spiral gears 34, 35 and 36, rotates asecond eccentric-block carrying stud 41 which through pitman 42 androcker arm 44 rocks shaft 45 which supports looper carrier 46.Underlooper 48 mounted on carrier 46 is thereby oscillated transverselyto the line of feed.

When the converted sewing machine has a reverse feed mechanism,provision for positive chainstitch formation may be made by installingthe mechanism disclosed in application Serial No. 151,680.

Conversion for Zigzag Stitching Provision for obtaining the lateralmovement for needle 15 is effected in the following manner. Main-shaft 5(see FIG. 1) is provided with bevel gear 51. A portion of the standard 2and of the arm 3 where they meet is machined away so that supportbracket 52 may be mounted by its horizontal section 54 to the undersideof arm 3 with a shaft supporting section 55 fitted within the hollowspace at the junction of the arm and standard. Portion 56 of section 55is bored to receive an anti-friction hearing 58 to provide an additionaljournal for main-shaft 5, and the cylindrically shaped vertical portionof section 55 is bored to provide a vertical journal for shaft 60. Theupper end of shaft 60 carries bevel gear 61 in mesh with gear 51 on themain-shaft, and the lower end carries eccentric-block 62.

Block 62 has a transverse slot 64 disposed perpendicularly to the axisof shaft 60 in which T-headed stud 65 may be adjustably fixed at someselected distance from the axis of rotation of shaft 60. A pitman 66 ispivotally connected with T-stud 65 at its lower end to transmit thereciprocating motion derived from the rotation of shaft 68 to providethe lateral throw for needle 15. It will be apparent that shifting theposition of stud 65 in slot 64 closer to the axis of rotation of block62 will reduce the extent of movement of the pitman and therefore thelateral excursion of needle 15, and conversely, that moving the studaway from the axis of rotation of block 62 will increase the lateralthrow of the needle. Stud 65 may be held in the desired adjustedposition in slot 64 by any suitable means such as for example themanually adjustable screw passing through the head of the stud asindicated in FIG. 1.

Various mechanisms have been used in the art for providing the lateralexcursion of the needle and also for adjusting the extent thereof. Theseare so well known that it seems unnecessary to expand further on suchmeans other than to mention that when extremely large lateral excursionsare involved, this type of eccentric drive means is not suitable. Sincethe lateral movements of the needle are continuous with such anarrangement, the needle may be moving laterally as it is penetrating thework which of course is objectionable. A more suitable arrangementtherefore would be the use of a cam and follower to drive pitman 66 andto provide a dwell in the lateral excursions of the needle as it ispenetrating the Work.

T he Perpendicular Guide Means for the Needle Support 68 (see FIGS. 2and 4) secured to the lower end of needle head 4, has a largehorizontally disposed slot 69 which receives the vertical guide member70 for lateral reciprocation thereof. Member '70 is T-form in shape, theupper horizontal section 71 being rectangular and dimensioned to fitsnugly, but freely in slot 69. Member 70 is moved transversely to theline of feed by a pivotal connection with pitman 66. Straps 72 whichconfine section 71 in slot 69 are held to support 68 by screws 74.

Guide member 70 has a vertical section 75 which depends downwardlytoward the cloth-plate. Section 75 has a rectangular slot 76 which alsoextends vertically and perpendicular to the cloth-plate. Needle-carrier78 fits snugly, but freely, in slot 76 so that the needle 15 carriedthereby may reciprocate normal to the cloth-plate regardless of thelateral position of guide member 70 as it is reciprocated by pitman 66.

Needle-carrier 78 receives its vertical reciprocation by a flexibleconnection with needle-bar 20 which consists of a linkage which changesthe vertical position of the lower end of the needle at each extreme ofthe lateral movement of guide member 70. Arm 80 held by clamp 81 (seeFIG. 6) on the lower end of needle-bar 20, has a portion 82 whichprojects horizontally toward the standard 2 and on which one or morehorizontally disposed pivot pins 84 are supported. Needle-carrier 78(see FIG. 5) also has a horizontally projecting portion on which one ormore horizontally disposed pins 85 are supported in parallel relation topins 84 but offset vertically therefrom.

6 A link 86 connects each pin 84 with each pin and these provide theconnection between needle-bar 20 and needlecarrier 78 to reciprocate thelatter.

Only one pin 84 and one pin 85 and one link 86 pivotally connecting thepins are needed for this drive connection. The walls of slot 76 couldmaintain the needle-carrier in perpendicular aspect, but wear in thewalls, much more likely to occur in high speed operation, would changethis desired perpendicular entry into the work by the needle. The use ofthe second set of pins 84 and 85 equally spaced from the first set ofpins as indicated in FIG. 1, and the connecting link 86 holds theneedle-carrier in the desired perpendicular relationship without theguidance of walls in the slot 76. This arrangement therefore serves tolessen the strain that would be imposed on these walls by the verticalreciprocation of needle-carrier 78, and also minimizes the effect thatwear in these walls would exert on proper guidance of theneedle-carrier.

The main purpose of this linkage however is to effect the change in theoverall length of the combination of the needle-bar, needle-carrier andneedle. As shown in FIG. 4, when pitman 66 has moved guide member 70 tothe extreme left, lower pin 85 on needle carrier 78 will have beenshifted to the left, and this shifting shortens the vertical distancebetween pins 84 and 85 as link 86 pivots about both. In this position,link 86 approaches a somewhat horizontal aspect. When pitman 66 movesguide member 70 to the right (as indicated in broken line in FIG. 4),lower pin 85 will be shifted to the right, and this will increase thevertical distance between the pins as the link is pivoted about them toapproach a somewhat vertical attitude. This change in distance providesthe compensation necessary for the previously mentioned inherentdifierence in timing between underlooper interceptions of the needlethread loop at the extremes of lateral movement of the needle.

The mechanisms so far described which provide lateral movement for theneedle coupled with perpendicular entry into the work and compensationfor the timing difference in the interaction of the underlooper andneedle are suitable for zigzag conversion of two thread chainstitchsewing machines having compound action underloopers and for lockstitchmachines which have hooks arranged so that the needle thread loop can beintercepted at both extremes of the lateral throw of the needle. Unlikethe case in lockstitching, in two thread chainstitching interception ofthe needle thread loop by the underlooper is only part of the stitchformation. It is also necessary for the needle to intercept theunderlooper thread to complete the stitch formation.

In the type of two thread chainstitching disclosed in application SerialNo. 30,682 utilizing the underlooper thread presentor, in a zigzagconversion in which the needle is provided with lateral movement, theneedle will not necessarily be in position to enter the underlooperthread triangle held about the limbs of the presentor when it is atextremes of its lateral movement. Since it is de sirable that the needleenter this triangle between the limbs of the presentor, some provisionmust be made for this lateral movement of the needle. This may be doneby utilizing a presentor having widely spaced limbs, but when thisconstruction is used, the wide spacing prevents either limb, dependingupon which extreme of lateral movement is being considered, fromeffectively controlling the needle thread loop on the underlooper fromthe preceeding interception of the needle thread. This can be overcomeby providing a third limb centrally disposed between the widely spacedlimbs which would then be efiective to control this intercepted needlethread loop on the underlooper in the same manner as the second limb ofthe thread presentor described in application Serial No. 30,682.

As an alternate thereto, the thread presentor may be provided with alateral movement matching thatof the needle, and this is the presentlypreferred embodiment;

Mechanism for Shifting the Thread Presenter Later-ally Alhough threadpresentor 29 is pivotally mounted on shaft 26, collar 88 normally ispositioned on shaft 26 so that it prevents arm from shifting laterally.In this modification, the position of collar 88 is adjusted so thatenough lateral movement of arm 25 on shaft 26 may be had. This movementis produced through shifting yoke 89 which has a pair of fingers 90either bored or slotted to fit freely on shaft 26 straddling the hub ofarm 25. The lower end of the shifting yoke has a clamp portion 91 bywhich the yoke may be secured to a laterally shifting shaft 94journalled in spaced bearings provided in a support casting 95 which isaffixed to the lower end of the support casting 31 in place of thebottom cover plate.

Shaft 94 is shifted laterally through a connection with the verticalguide member 70 and therefore travels in unison with the lateralmovement of the guide member and the needle-carrier 78 guided thereby.This connection is in effect a large bellcrank lever shown as consistingof a number of connected parts. Obviously other mechanisms could besubstituted for this connection to effect the desired synchronousmovement of the yoke 89 with guide member 70.

As shown, the arrangement comprises a vertical shaft support bracket 96which is mounted within the standard 2 to provide a vertical journal forshaft 98. The lower end of shaft 98 carries an arm 99 which connectsthrough a pair of ball joints 100 and 101 at either end of rod 102 withan arm 104 clamped on shaft 94. The upper end of shaft 98 carries arm105 clamped thereto which is pivotally connected through a second pitman106 with the same section of guide member 70 to which pitman 66 isattached.

This arrangement provides a fixed relationship between the throwlaterally of the needle and the lateral shifting of the thread presentor29 to maintain the desired relationship between them. Setting thisrelationship is effected by positioning arm 25 on shaft 26 by adjustingthe lateral position of yoke 89 on the shifting shaft 94 after looseningthe screws in clamp 92. This adjustment normally would be made with thelateral throw of the needle reduced to zero so that the needle movesonly vertically on the median line of its lateral movement, with theneedle centered in the transverse needle slot in the needle-plate anddisposed centrally between the limbs of presentor 29. As mentioned, thisreduction of movement is obtained by adjusting the position of T-stud 65toward the center of rotation of eccentric-block 62.

When the parts have been so positioned, it may subsequently be desiredto shift the central position of the needle slightly in either directionlaterally. This is done by manipulating an eccentric in the commonpivotal connection of the pitmans 66 and 106 at the end of section 71 ofvertical guide 70. As may be seen in FIG. 4, this connection is effectedthrough an eccentric-headed stud 108 which has a concentric shaftportion 109 which is freely received in the yoked end of section 71 andthrough the end of pitman 106 held between the arms of the yoke. Theeccentric head 110 is held within the clamp 111 at the end of pitman 66,and this clamp may be loosened to permit stud 108 to be rotated manuallyby means of the pierced tang 112 at the lower end of the stud. It isapparent that rotation of stud 108 will change the lateral position ofmember 70 and since pitman 106 is connected thereto, this willautomatically shift the lateral position of yoke 89 and presentor arm 25in synchronism with the shifting of needle-carrier 78.

It was previously mentioned that in lockstitch sewing machines having ahook operating along the line of feed that some provision for laterallyshifting the hook in synchronism with the shifting of the needle isnecessary to convert the machines for zigzag stitching. In suchmachines, if the hook-shaft is modified so that it may move laterallywhile maintaining its rotating drive connection, then some additionalconnection with this hook-shaft u may be made through a shift membersuch as yoke 89 or some equivalent mechanism to shift the hook in unisonwith the lateral throw of the needle.

While various embodiments of the invention have been described andcertain modifications suggested, it will be understood that changes andelaborations may be effected in the various parts without departing fromthe general principles disclosed herein and the scope of the inventionis therefore defined by the appended claims.

What is claimed is:

1. In a two thread chainstitch sewing machine having a reciprocatingneedle-drive-bar, and actuating means therefor; a threaded underlooperoperating transversely to the line of feed, and actuating meanstherefor; an underlooper thread presenting member operating along theline of feed and about whose limbs the underlooper thread triangle isformed, and actuating means therefor; said presenting member beingmounted for bodily movement transversely to the line of feed as well asalong the line of feed; means for producing a zigzag stitch comprising asupport fixed to the machine, a member having vertical guide meansthereon mounted on said support so that it can move laterally only, andactuating means to impart lateral reciprocation to the guide member; aneedle-carrier, and a threaded needle supported thereby; said needlecarrier being connected with said member for guided verticalreciprocation as said guide member moves laterally; means connecting theneedle-drive-bar and the needlecarrier to impart vertical reciprocationto the needlecarrier simultaneously with its lateral movement with theguide member; and means connected with the guide member to shift theunderlooper thread presenting member laterally in unison with the guidemember.

2. A sewing machine in accordance with claim 1 in which the means forshifting the underlooper thread presenting member laterally comprises ayoke mounted for movement transversely to the line of feed, said yokebeing maintained in engagement with the thread presenting member; andmechanism connecting the yoke with the guide member to shift the yoke inunison with the lateral movement of the guide member.

3. A Zigzag sewing machine having a vertically reciprocating needle-barand a needle carried thereby; actuating means to impart reciprocation tosaid needle-bar; said needle-bar being mounted for movements laterallyacross the line of feed, and means for imparting lateral movements tothe needle-bar including a shiftable support for said needle-bar and anarm connected with said support; a loop-taker operating along the lineof feed, and actuating means therefor; said loop-taker being mounted forbodily movement transversely to the line of feed as well as along theline of feed; means for shifting the loop taker transversely to the lineof feed; said last-named means including a second arm connected to theshiftable support; the connections for both arms with the shiftablesupport being common and including a manipulatable eccentric whoseposition in said common connections may be adjusted to fix the lateralposition of the needle-bar and the loop-taker simultaneously withoutaffecting the extent of the lateral movements of either.

4. A sewing machine according to claim 1 in which there is an armconnected with the vertical guide member and in which the means forshifting the underlooper thread presenting member laterally includes asecond arm connected to the vertical guide member, the connections forboth arms with the guide member being common and including amanipulatable eccentric whose position in said common connection may beadjusted to fix the initial lateral position of the needle-carrier andof the thread presenting member simultaneously without affecting theextent of lateral movement of either.

5. In a sewing machine having a reciprocating needle drive-bar andactuating means therefor; a loop-taker actuating means therefor; meansfor producing stitch comprising a support fixed to the ma her havingvertical guide means thereon mounted on said support so that it can movelaterally only, and actuating means to impart lateral reciprocation tothe guide member; a needle-carrier and a threaded needle supportedthereby, said needle-carrier being guided for vertical reciproeation bythe guide means on the guide member as the latter moves theneedle-carrier laterally; a pair of pivots spaced a predetermineddistance apart laterally on the needle-drive-bar; a second pair ofpivots spaced the same predetermined distance apart laterally on theneedle carrier; and parallel links connecting the pivots on theneedledrive-ba-r and the needle-carrier, said arrangement beingefieotive to maintain the needle-drive-bar and the needle carrier insubstantial axial parallelism as the guide member moves laterally andthe needle-drive-bar is reciprocated vertically.

6. A sewing machine having a vertically reciprocating needle-drive-barand actuating means therefor; a needlecarrier; a connection between saidneedle-drive-bar and the needle-carrier for imparting verticalreciprocation to the needle-carrier While permitting concurrenthorizontal reciprocation thereof; means for reciprocating saidneedlecarrier horizontally as it is reciprocated vertically; and meansfor maintaining said needle-drive-bar and the needle-carrier insubstantial axial parallelism during the concurrent needle-carrierreeiprocations, said connection and said means for maintaining axialparallelism comprising a pair of pivots spaced a predetermined distanceapart laterally on the needle-drive-bar, a corresponding pair of pivotsspaced the same predetermined distance apart laterally on theneedle-carrier, and parallel links connecting the respective pivots onthe needle-drive-bar and the needle-carrier.

References Cited in the file of this patent UNITED STATES PATENTS326,724 Dewey Sept. 22, 1885 929,698 Onderdonk Aug. 3, 1909 1,232,263Finch July 3, 1917 2,029,942 Rapaport et al. Feb. 4, 1936 2,107,271Allen et al. Feb. 8, 1938 2,324,836 Hale July 20, 1943 2,344,632 ParryMar. 21, 1944 2,635,568 Gellman et a1 Apr. 21, 1953 3,026,831 JohnsonMar. 27, 1962 3,058,436 Goosman' Oct. 16, 1962 FOREIGN PATENTS 603,984Germany Oct. 12, 1934

1. IN A TWO THREAD CHAINSTITCH SEWING MACHINE HAVING A RECIPROCATINGNEEDLE-DRIVE-BAR, AND ACTUATING MEANS THEREFOR; A THREADED UNDERLOOPEROPERATING TRANSVERSELY TO THE LINE OF FEED, AND ACTUATING MEANSTHEREFOR; AN UNDERLOOPER THREAD PRESENTING MEMBER OPERATING ALONG THELINE OF FEED AND ABOUT WHOSE LIMBS THE UNDERLOOPER THREAD TRIANGLE ISFORMED, AND ACTUATING MEANS THEREFOR; SAID PRESENTING MEMBER BEINGMOUNTED FOR BODILY MOVEMENT TRANSVERSELY TO THE LINE OF FEED AS WELL ASALONG THE LINE OF FEED; MEANS FOR PRODUCING A ZIGZAG STITCH COMPRISING ASUPPORT FIXED TO THE MACHINE, A MEMBER HAVING VERTICAL GUIDE MEANSTHEREON MOUNTED ON SAID SUPPORT SO THAT IT CAN MOVE LATERALLY ONLY, ANDACTUATING MEANS TO IMPART LATERAL RECIPROCATION TO THE GUIDE MEMBER; ANEEDLE-CARRIER, AND A THREADED NEEDLE SUPPORTED THEREBY; SAID NEEDLECARRIER BEING CONNECTED WITH SAID MEMBER FOR GUIDED VERTICALRECIPROCATION AS SAID GUIDE MEMBER MOVES LATERALLY; MEANS CONNECTING THENEEDLE-DRIVE-BAR AND THE NEEDLECARRIER TO IMPART VERTICAL RECIPROCATIONTO THE NEEDLECARRIER SIMULTANEOUSLY WITH ITS LATERAL MOVEMENT WITH THEGUIDE MEMBER; AND MEANS CONNECTED WITH THE GUIDE MEMBER TO SHIFT THEUNDERLOOPER THREAD PRESENTING MEMBER LATERALLY IN UNISON WITH THE GUIDEMEMBER.